Column heater



FIG. 1 is a perspective view of a column heater;

FIG. 2 is a front view of the column heater;

FIG. 3 is a back view of the column heater;

FIG. 4 is a top view of the column heater; and,

FIG. 5 is a bottom view of the column heater.

The broken lines indicate unclaimed portions of the article that form nopart of the claimed design.

CLAIM The ornamental design for a column heater, as shown and described.